1. Field of the Invention
The present invention relates; to an exposure precision tester for measuring automatic exposure precision of a camera in a state of a finished product, a photometric unit used for the exposure precision tester, the camera to which adjusted values obtained by the exposure precision tester are applied, and an exposure precision testing method.
2. Related Art Statement
A conventional exposure precision test for a camera is performed for checking whether a diaphragm aperture mechanism and a shutter mechanism of a camera in a state of a finished product operate normally, and in particular, for checking whether specified exposure precision can be obtained for specified subject brightness at automatic exposure. In the case of a camera using a roll of 135-formatted film, this checking is performed after assembly completion of the camera by opening its back lid, irradiating the camera with light that is a standard, from the front of a film mask, and activating the camera and making the camera store the discrepancy from correct exposure, or adjusting the camera so as to get the correct exposure.
FIG. 9 shows a conventional exposure precision tester 1 for performing an exposure test (an EE (electric eye) check) to a roll of 135-formatted film, and an exposure adjuster (an EE adjuster) 3 and a camera support mechanism 4 are located at the opposite sides of each other on a base 2. The EE adjuster 3 has a housing 5, where a light source such as a halogen lamp, a reflector reflecting the light from the light source, data write means for storing detected exposure energy as data, and a controller (all: not shown) controlling the light source and other members are located In addition, a diffuser 6 comprising a ground glass and the like for making the light reflected by the reflector be uniform surface light is provided in the side of the camera support mechanism 4.
The camera support mechanism 4 comprises a horizontal guide mechanism 7 extending straight toward the EE adjuster 3, a slider 8 horizontally moving along this guide mechanism 7, a sensor mount 9 mounted on the slider 8, and a camera stage 11 supported by a vertical adjustment mechanism 10 provided on the sensor mount 9. The vertical adjustment mechanism 10 has a vertical adjustment knob 12, and a rack engaging a pinion that is the center of rotation of the vertical adjustment knob 12, the camera stage 11 is supported at the top of this rack 13, and a camera (not shown) is mounted on the camera stage 11.
On the sensor mount 9, a sensor support plate 14 having a photometric sensor 15 is mounted The photodetecting surface of the photometric sensor 15 faces the path of the light emitted from the EE adjuster 3, and hence, the photodetecting surface receives the light passing through the shutter of the camera (not shown) mounted on the camera stage 11, and further, it detects the exposure energy of the camera. A shielded wire 17 having a connector 16 at the free end is connected to photometric sensor 15, and outputs the exposure energy to the EE adjuster 3 by the connector 16 being connected to the EE adjuster 3.
In the above-mentioned exposure precision tester 1, a camera in a state of a finished product is mounted on the camera stage 11, and the EE check is performed. The camera is mounted on the camera stage 11 with a back lid of the camera being opened, and the photometric sensor 15 is made to face a film mask surface of the camera by adjusting the slider 8 and vertical adjustment mechanism 10. Then, the camera performs an exposure operation corresponding to the standard light that has constant brightness and is emitted from the picture-taking lens side of the camera, and the tester 1 measures EE precision by the light energy received by the photometric sensor 15 through this exposure operation.
By the way, recently, cameras are on the market that each adopt a drop-in loading method for simple loading of a film cartridge. For example, cameras each using an IX240 film cartridge have the construction that it becomes possible to take a picture since the film is automatically fed from the film cartridge by opening a lid (bottom lid) of a film cartridge cell, inserting a film cartridge, and merely closing the lid thereafter.
In this drop-in loading type of camera, a back lid is not necessary, and hence, the lid of a camera in a state of a finished product is blocked. Therefore, a film mask surface can not be seen from the outside, and hence, it is not possible to perform the EE adjustment by using the above-mentioned exposure precision tester 1 having the measurement condition that its back lid is left open. For this reason, the EE adjustment of the drop-in loading type camera is not performed in the state of a finished product, but it should be performed at the stage in an assembly process before completion, the stage when the film mask surface is exposed.
However, if the EE adjustment is performed on a middle stage of assembling, EE adjusted values may shift at the succeeding assembly processes, and hence, in this case, this camera is shipped as a finished product, as it is. Since EE exposure is not guaranteed as a finished product because of this, there is a possibility that this camera does not function favorably as a camera, which is not good.
In addition, if the EE adjustment is performed again after becoming a finished product, this type of camera must be disassembled until the stage where the EE adjustment is possible because of exposure of the film mask surface Further, the camera must be reassembled thereafter, and hence, a large amount of time and labor must be consumed. This is a problem that occurs every repair of this type of camera, and is a cause by which much time and labor becomes necessary for repair.